This invention relates to the manufacture of pyrollidones (or lactams) such as 2-pyrrolidone, N-methyl-2-pyrrolidone and N-(beta-hydroxyethyl)-2-pyrrolidone, the latter being capable of undergoing catalytic dehydration to provide N-vinyl-2-pyrrolidone.
2-Pyrrolidone and its N-substituted derivatives have achieved considerable commercial importance, notably as solvents and monomers, and a variety of synthetic procedures have been proposed for their manufacture.
U.S. Pat. No. 2,267,757 to Schuster describes a process for obtaining N-alkyl, cycloalkyl, aralkyl or aryl pyrrolidones by reacting gamma-butyrolactone with primary amines at elevated temperature in the presence of catalysts splitting off water. U.S. Pat. No. 2,351,939 to Drossbach, et al. discloses the production of lactams by passing a vaporized dicarboxylic acid of at least four, and preferably six, carbon atoms with ammonia and hydrogen over catalysts having a hydrogenating and dehydrating action, e.g., conventional hydrogenation catalysts such as nickel, cobalt and copper and conventional dehydration catalysts such as phosphoric acid and boric acid. U.S. Pat. No. 2,669,570 to Schnizer discloses that N-vinylpyrrolidone is obtained by reacting ethanolamine with gamma butyrolactone to form N-beta-hydroxyethyl-gamma-hydroxybutyramide and then subjecting the amide to dehydration. In accordance with U.S. Pat. No. 2,674,602 to Schuster, N-alkyl lactams are obtained by reacting N-unsubstituted lactams with alcohols in the presence of catalysts for splitting off water. According to U.S. Pat. No. 2,843,600 to McKeever, alkyl beta-cyanopropionate is converted to 2-pyrrolidone by mixing a nickel hydrogenation catalyst with an inert organic liquid, supplying hydrogen under pressure to the mixture, heating the mixture to 150.degree.-260.degree. C. under agitation and adding a lower alkyl beta-cyanopropionate. The reaction mixture is maintained during the conversion of cyanopropionate to 2-pyrrolidone at 150.degree.-300.degree. C. and 200-5,000 psi or more. U.S. Pat. No. 3,080,377 to Liao describes the reductive aminolysis of succinic anhydride to produce 2-pyrrolidone. U.S. Pat. No. 3,095,423 to Copenhaven, et al. describes the hydrogenation of succinonitrile in the presence of water to provide 2-pyrrolidone and split out ammonia. The process of Prince U.S. Pat. No. 3,637,743 produces 2-pyrrolidone and N-substituted-2-pyrrolidones in one step by the carbonylation of allyl chloride in the presence of ammonia in a two phase solvent system, e.g., benzene and water. In U.S. Pat. No. 4,123,438 to Geurts, et al., a process for the preparation of 2-pyrrolidone is described in which succinonitrile is hydrogenated in the liquid phase in the presence of ammonia at 50.degree.-200.degree. C. and at a partial hydrogen pressure of 1.150 atmospheres and the resulting product is hydrolyzed. U.S. Pat. No. 4,181,662 to Sweeney describes the production of 2-pyrrolidone by hydrolyzing succinonitrile and hydrogenating the resulting hydrolysate in the presence of a heterogenous hydrogenation catalyst at 200.degree.-300.degree. C. and 100-10,000 psig. U.S. Pat. No. 4,183,866 to Kurkov discloses the production of 2-pyrrolidone by contacting 3-cyanopropanol with hydrogen in the presence of a prereduced copper chromite catalyst to yield a mixture of 3-cyanopropanol and gamma-butyrlactone and thereafter contacting said mixture with aqueous ammonia to convert the 3-cyanopropanol to 2-pyrrolidone.